Sink



FIG. 1 is a perspective view of a sink, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top view thereof.

A bottom of the sink may not been seen in use and does not have design features, so a bottom view thereof is omitted. 

CLAIM The ornamental design for a sink, as shown and described. 